1. Field of the Invention
The present invention relates to three-dimensional image-capturing apparatuses, and in particular, to a three-dimensional image-capturing apparatus that obtains a three-dimensional image (stereo-image) by capturing a plurality of images of the same subject which have parallax and that determines the distance to the subject.
2. Description of the Related Art
For forming a three-dimensional image, a plurality of images obtained by viewing the same subject from a plurality of different points, that is, images having parallax, must be captured. Accordingly, in general, a single three-dimensional image-capturing apparatus is provided with two cameras, and two images of a subject, viewed from two different positions, are captured by the two cameras.
The use of the two cameras increases the entire size of the three-dimensional image-capturing apparatus, which causes a problem in that the size cannot be reduced.
In the case where a three-dimensional image-capturing apparatus is constructed using a plurality of separate camera units, the optical axes of the camera units must be aligned. However, it is very difficult to align the optical axes of the separate camera units.
In the case where a three-dimensional image-capturing apparatus is provided with a plurality of cameras, the cameras must be externally synchronized for processing the picture signals. This inevitably requires a circuit for establishing synchronization, which causes an increase in the price of the three-dimensional image-capturing apparatus.